1. Field of the Invention
This invention relates to a thin film transistor (TFT) array used for driving pixels in active matrix type liquid crystal display (LCD) devices and a method of manufacturing the same.
2. Description of the Prior Art
TFT arrays have recently been used in LCD devices having a large number of pixels for constituting a high contrast display.
Typical conventional methods for producing TFT arrays are disclosed in Japanese Laid-Open Patent Applications No. 58-14568 and No. 59-113667. These methods comprise a self alignment process and a lift-off process. The lift-off process is used for forming the impurity-doped semiconductor layer and the source and drain electrodes by using a resist on the protective insulating layer above the TFT channel portion. In the conventional method using the lift-off process, however, it was difficult to completely remove the resist from the insulating layer. Also, it was difficult to activate the impurity in the intrinsic semiconductor layer because of the deposition at a low temperature. The TFT array is further required to have such a structure that undesired parastic capacitances should be as small as possible and that the channel portion should be subjected to less external light.